This year as I watch my friends and family send their little ones off to school, I, too, am starting a new educational journey. I’m taking piano lessons. I’ve wanted to play since I was a child but never had the opportunity. My husband heard me talk about wanting to play a few times, so he suggested giving me lessons and a piano as a gift for our first wedding anniversary.

I literally thought about it for a full day. I was completely touched that my husband wanted to help me accomplish a lifelong dream. However, did I really want to commit myself to something completely out of the ordinary? I learned to play the trumpet in middle school and played through high school, so I can read music—treble clef. I’ve never had to learn bass clef or how to make my left hand and right hand play different music at the same time. Could I do it? What if I’m the worst adult student my teacher has ever had?

I came to the realization that the accomplishments of which I’m most proud pushed me out of my comfort zone. Plus, how could I possibly say no to my husband when his gesture was so sweet? I’ve had one lesson so far and the idea of being able to coordinate my hands still seems a little like being able to rub my stomach while patting my head. However, I’m excited about the future and am hoping I’ll be playing well by the holidays!

Every issue of Roofing has an educational bent, but this issue may push you out of your comfort zone. For example, cool roofs have been a hot topic for many years. Conventional wisdom states cool roofs are not appropriate for northern climates. Kurt Shickman, executive director of the Washington, D.C.-based Global Cool Cities Alliance, will challenge that notion in “Cool Roofing”. He presents new evidence from several scientific studies that demonstrate cool roofs provide benefits to buildings in Climate Zones 4 through 8.

Meanwhile, Thomas W. Hutchinson, AIA, FRCI, RRC, CSI, RRP, principal of Hutchinson Design Group Ltd., Barrington, Ill., and a member of Roofing’s editorial advisory board, shares his in-the-field experiences regularly. He notes in “From the Hutchinson Files” that code-mandated insulation thicknesses are forcing designers to take roof access door and clerestory sill details seriously. Hutch’s goal with his article is to give designers some confidence to create appropriate design and detailing solutions.

These articles may challenge what you’ve always done but they’re worth considering and discussing. In fact, I’d really like to hear what you think about them. In return, I’ll keep you updated on whether I’m becoming the next Chopin!

PHOTO 1: The new roof has been installed at SD 73 Middle School North and it can clearly be seen that the door and louver need to be raised. On this project, there were four such conditions.

The most common concern I hear related to increasing insulation thickness (a result of increased thermal values of tapered insulation), especially in regard to roofing removal and replacement, is, “OMG! What about the roof access door and/or clerestory?” You can also include, for those knowledgeable enough to consider it, existing through-wall flashing systems and weeps.

I’m a bit taken aback by this concern; I have been dealing with roof access doors and clerestory sills for the past 30 years and, for the most part, have had no problems. My first thought is that roof system designers are now being forced to take these conditions seriously. This is a big deal! They just have no clue.

In the next few pages, I’ll review several possible solutions to these dilemmas, provide some detailing suggestions and give you, the designer, some confidence to make these design and detailing solutions. For the purpose of this article, I will assume reroofing scenarios where the challenge is the greatest because the conditions requiring modification are existing.

THE ACCESS DOOR

For many and perhaps most contractors who sell and, dare I say, design roofs, it is the perceived “large” expense of modifying existing conditions that is most daunting. Often, these conditions are not recognized until the door sill is several inches below the new roof sur- face. Not a good predicament. Planning for and incorporating such details into the roof system design will go a long way to minimizing costs, easing coordination and bringing less tension to a project.

PHOTO 2: The sill has been raised and new hollow metal door, frame and louver have been installed at SD 73 Middle School North. Door sill and louver sill flashing are yet to be installed, as are protective rubber roof pavers.

Door access to the roof is the easiest method to access a roof. These doors are typically off a stair tower or mechanical penthouse and most often less than 12 inches above the existing roof as foresight was not often provided (see photos 1, 2 and 6 through 9). With tapered insulation thickness easily exceeding 12 inches, one can see that door sills can be issues with new roof systems and need to be considered.

Designers should first assess the condition of the door and frame, typically hollow metal. Doors and frames that are heavily rusted should not be modified and reused, but discarded, and new ones should be specified. The hardware too needs to be assessed: Are the hinges free of corrosion and distortion? Is the closure still in use or detached and hanging off the door frame? The condition of door sweeps, knobs, lockset and weather stripping should also be determined. Ninety-nine percent of the time it is prudent to replace these parts.

As the roof system design develops, the designer should start to get a feel for the thickness of insulation at the door. It is very important the designer also consider the thicknesses that vapor retarders, bead and spray-foam adhesives, cover and board and protective pavers will add. These can easily be an additional 4 inches.

PHOTO 3A: The new roofing at SD 73 Elementary North was encroaching on this clerestory sill and required that it be raised. As part of this project, the steel lintel was exposed. It was prepped, primed and painted and new through-wall flashing was installed.

Once the sill height is determined, the design of the sill, door and frame can commence. If the sill height to be raised is small—1 1/2 to 3 inches—it can often be raised with wood blocking cut to fit the hollow metal frame, flashed with the roofing membrane, metal sill flashing and a new door threshold installed, and the door and frame painted. This will, of course, require the removal of the existing threshold and door which will need to be cut down to fit and then bottom-sealed with a new metal closure (see details A and B, page 3).

When the door sill needs to be raised above 3 inches, the design and door considerations increase. Let’s consider that the door and frame is set into a masonry wall of face brick with CMU backup. Although most hollow metal doors are 7 feet 2 inches to match masonry coursing, after the modification the door may be shorter. For example, if a door is 7 feet 2 inches and you must raise the sill 5 inches, the new door and frame will need to be 6 foot 9 inches.PHOTOS & ILLUSTRATIONS: Hutchinson Design Group Ltd.

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November/December 2018

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About Roofing

Roofing is a national publication that unravels, investigates and analyzes how to properly design, install and maintain a roof system. Through the voices of professionals in the field, Roofing’s editorial provides a unique perspective.